Dzyaloshinskii-Morija interaction and local magnetic anisotropies in U2Pd2In : Ground state and metamagnetic transition

Abstract

${\mathrm{U}}_{2}{\mathrm{Pd}}_{2}\mathrm{In}$ is the material where the elements of the geometrical frustration of the lattice coexist with strong spin-orbit coupling (SOC). The ground state of the system is a noncollinear planar magnetic structure with orthogonal atomic magnetic moments. There are three possible physical mechanisms that can lead to this nontrivial magnetic structure: frustrated isotropic exchange interaction, Dzyaloshinskii-Morija interaction (DMI), and magnetic anisotropy. Our first-principles calculations show that in the case where the SOC is neglected, and therefore the DMI and magnetic anisotropy are absent, the ground state structure is the collinear ferromagnetic one. The leading contribution to the stabilization of the magnetically compensated configuration of orthogonal atomic moments is provided by the local magnetic anisotropy of the U moments. A weaker DMI leads to the lifting of the degeneracy between the magnetic states with different local chirality. The established hierarchy of the interactions allows us to explain the metamagnetic phase transition in the in-plane external magnetic field. The analysis of the noncollinearity of the spin and orbital moments of the same U atom appearing in the applied external field show that the trend to the antiparallel orientation of the two atomic moments following from the third Hund's rule is much stronger than the trend to the parallel orientation of the moments due to the applied external magnetic field.